A polymer gas barrier film (e.g., plastic film) that is inexpensive and exhibits excellent workability has been provided with a desired function, and used in various fields.
For example, a gas barrier plastic film that does not allow water vapor and oxygen to pass through has been used as a food/drug packaging film in order to suppress oxidation and denaturation of proteins, oils, fats, and the like to keep taste and freshness. In recent years, use of a transparent plastic film as an electrode substrate instead of a glass plate has been studied for displays (e.g., liquid crystal display and electroluminescence (EL) display) in order to implement a reduction in thickness, a reduction in weight, an improvement in flexibility, and the like.
For example, Patent Document 1 discloses a flexible display substrate in which a transparent gas barrier layer formed of a metal oxide is stacked on a transparent plastic film, and Patent Document 2 discloses a gas barrier film that includes a polysilazane film that is formed on at least one side of a film, and subjected to a plasma treatment.
However, the gas barrier films disclosed in Patent Documents 1 and 2 have a problem in that cracks may occur in the gas barrier layer so that the gas barrier capability may decrease, or a sufficient gas barrier capability may not be obtained unless the thickness of the gas barrier layer is increased to a micrometer level. Moreover, since a plastic film tends to allow water vapor, oxygen, and the like to pass through as compared with a glass plate, elements provided in a display may deteriorate. The gas barrier films disclosed in Patent Documents 1 and 2 may also exhibit poor transparency and heat resistance.